Oxygenator



Dec. 3, 1963 1-. H. GEWECKE ETAL 3,112,746

OXYGENATOR Filed Sept. 18, 1956 co AND EXCESS o Ll} lO""" m ll venousBLOODASJ AKTERiAL BLOOD Cyrus A. Bra/nan INVENTOR.

United States Patent 3,112,746 OXYGENATOR Theodore H. Geweelre,Glenview, and Qyrns lR. Bronian, Evanston, Eli, assiguors to BanterLaboratories, lnc. Filed Sept. 18, 1956, Ser. No. illdd '7 Claims. (=Cl.123-214) This invention relates to an oxygenator and the method ofproducing the same, and more particularly, to an oxygenating device fortreating human blood as a substitute for the human heart and lungs.

Although oxygenating devices for human bloods have been known and usedfor a considerable time, the recent work of Dr. C. Walton Lillehei atthe University of Minnesota Medical Hospital and others has firmlyestablished the role of inexpensive, disposable forms of such devices.The device of our invention is an improvement on the oxygenatordescribed in an article by Dr. Lillehei in Diseases of the Chest, volumeXXIX, No. 1, January 1956.

Our invention has several significant advantages over the ox genatorprovided by those previous in the art. Of outstanding importance is itsinexpensiveness of cost. Employing, as it does, heat-scalablethermoplastic material constructed into a unitary device, it isrelatively inexpensive to produce. Thus, its use is imrnediatelyavailable to many more patients than the cumbersome, expensivearrangements previously described. Being of a flexible material, it iscompactly transported and stored. Because of its unitary nature, it isimmediately available for use without the need for making tediousconnections.

It is to be appreciated that the role of an artificial heart-lung has byno means been fully investigated. Current usages are in cardiac surgerysuch as the renoumed blue baby operations. Certain repairs on humanhearts are now performed with the aid of artificial heartlungs so as torender the heart immobile during the delicate surgical proceduresfollowed. With the increasing awareness of the destructive character or"heart ailments, it is entirely possible that usages now consideredimpractical may come into being. For example, post-cardiac stroketherapy may require immobilization of the heart so as to preventcomplications and possibly death. For this purpose, our invention iseminently qualified.

The oxygenator of our invention is intended for use with conventionalpumping equipment and tubular conduits connecting the device to a majorheart vein and heart artery. Our oxygenator includes a pair ofheatsealable, thermoplastic materials in sheet form, heat sealedtogether to provide chambers for receiving oxgenation and defoaming ofvenous blood from a patient having an immobilized heart.

The oxygenator of our invention will be described in conjunction withthe accompanying drawing in which FIG. 1 is a schematic View of anartificial heart-lung system; FIG. 2 is an elevational view of theoxygenator of our invention; and FIG. 3 is a cross-sectional view takenalong the lines 33 of FIG. 2.

Referring now to the drawing, and in particular FIG. 1 wherein aschematic arrangement of an artificial heartlung apparatus is pictured,the numeral 1d designates the oxygenator of our invention. Four conduitscommunicate with oxygenator it Conduit 11 connects a source of venousblood of a human being to oxygenator 10. Such a source might be thesuperior and inferior vena cavae. In the oxygenator, this carbondioxide-bearing blood is intimately contacted with pure oxygen enteringthrough conduit 12. After carbon dioxide-oxygen exchange has beenachieved, the excess gases are vented from oxygenator it} through vent13. The oxygenated blood, now designated arterial blood, leavesoxygenator 10 through conduit 14 and returns to the patients arterialsystem. This entry can be made through the aorta which is reached bymaking a small slit in the subclavian artery, the main channel to theleft arm.

Aiding in the flow of blood to and from oxygenator 1b are pumpsdesignated P which conveniently may take the form of a finger pump.

Also provided in the artificial heart-lung system is a source of heartto maintain the oxygenator and its associated blood at the propertemperature. Such a source is designated H in FIG. 1 and convenientlymay assume the form of a heat lamp.

Referring now to FIG. 2, oxygenator 10 is shown in enlarged and detailedform. Also shown as communicating, flexible plastic tubes communicatingwith oxygenator ltd are conduits ll, 12 and 14 previously referred to inconnection with FIG. 1. The oxygenator of our invention is essentiallyrectangular and is constructed of two fiat sheets of heat-scalable,translucent plastic material arranged in face-to-face relation and heatsealed along the longer sides and one end thereof as indicated at 15 and16. Also heat sealed to the sealed end of oxygenator it? is a plastichanger strap 17 which permits convenient supporting of oxygenator itfrom a vertical standard such as shown in partial form and designated13. A modification employs the provision of a second heat seal parallelto and spaced from 16, the portions of side seals 15 being open betweenthe two spaced seals, permitting the insertion of a rod so that theoxygenator is suspended like a curtain.

When the oxygenator of our invention is not filled with blood the twosheets comprising the main body portion of the oxygenator are disposedin faceto-face, lay-fiat relationship as can be appreciated from aconsideration of FIG. 3 wherein a portion of the oxygenator is shown incross section. In PEG. 3 one sheet is designated 19 and the other sheet29. Sheets 19 and 21') are heat sealed together along three of theirsides as at 15 and 16, as indicated above. The sheets are additionallyheat sealed along a longitudinal line parallel to seals 15 and locatedbetween the two sides, but closer to one of the side seals 15 as isdesignated 21 in F G. 2. The longitudinal passage or chamber achieved bythe cooperation of one seal 15 and seal 21 is used as an oxygenating orbubbling chamber. The end 22 of this chamber 23 opposite heatsealed end116 is closed by a lateral heat seal 22a. Conduits it and 12 are heatsealed into this seal so as to communicate with chamber 23.. The end ofchamber 23 adjacent sealed end 16 communicates with the remainingportion :of the envelope formed by heat sealing sheets 19 and 24?together. This major remaining portion of the envelope is provided witha series of heat seals along transverse lines, generally designated 24.One transverse line 244:, along which sheets 19 and it are heat sealedtogether, is generally of a V configuration, one end of the V beginningat the end of heat seal 21. The trapezoidal chamber adjacent the top ofchamber 23 and formed by heat seals in", lo and 2 in, is employed as adebubbling or detoaming chamber. The interior walls of the envelope aresiliconized at this area to more readily cause oxygen and otherentrapped gas such as carbon dioxide, to leave the blood. The freed gasthen may issue through vent 13 provided in heat seal 15 at one side ofthe debubbling chamber 25.

To strip the blood of any remaining gas, we provide a tortuous outletpassageway achieved by heat sealing a second V-type configuration as a2417, which is spaced from and opposed to seal at 2 311, and a thirdspaced V configuration heat seal as at 24c, parallel to 24a, but opposedto 2412. An additional line heat seal is provided at 2 4d to establish aregular passage for the blood to exit through conduit serpentine orzigzag passageway achieved by j r sheets and with the foregoingheat-sealing operations is enlarged at the points of change of passagedirection especially at 26 and 27. The slowing up of blood flow at thesepoints more readily enables any entrapped gas to become dissociated withthe main body of blood.

To further enable the blood to rid itseli oi entrapped oxygen and carbondioxide and to permit these gases to find their way to vent 13, weprovide upwardly-extending tongue-like projections 23 which areheat-sealed to the inner Walls of sheets 19 and 2d and can be betterappreciated from FIG. 3. Projections 23 act like dams or weirs for theblood coursing through the zigzag passage, errnitting the major portionof it to flow rapidly alongside of projection 23 as indicated at 29 inFIG. 3. The blood flowing over the top of projection 28 as at '39, ilowsmore slowly and therefore, does not oppose the natural tendency ofbubbles 31 to attempt to rise and pass into a higher branch of thezigzag passage. Without the provision of projections 28 the rapid flowof blood at the point of change in direction of zigzag passage mightsubstantially prevent any entrapped gas from finding its way around theV configuration.

Referring again to H6. 2, it is to be noted that a filter 14a is heatseal d into the exit portion of the zigzag passageway and communicateswi h conduit 14-. Also referring to PEG. 2, it is to be noted that thereis a portion of the envelope yet unheat-sealed into an enclosure asindicated at 32.. This triangular-shaped portion provides a convenientstorage space for conduits ll, 12 and 14 during transport and storage ofthe ox genator of our invention. It is also possible to intermit ndyheat seal the portion of the open end of the envelope as at to retainany equipi rent such as conduits within the confines of the envelope.

In the manufacture of our oxygenatcr, two sheets of thermoplasticmaterial such as polyvinyl chloride are disposed in faceto-facerelationship and trimmed to the proper shape. Sh rt line seals are madeat positions designated 34 which serve to define the change of directionpoints of the passage to be provided later. Aligned with and spaced fromtack seals at positions 34 are tonguedilce projections 23 which are thenheat sealed into position by sealing the edges of projections 28 one tosheet 19 and the other to sheet 2%. f'rojections 28 are constructed ofthe same material as sheets 19 and Zll. The oxygenator is then.completed by one heat-sealing operation wherein mating dies provide heatseals l5, E6, 21, 22a and include utlet connections for the threeconduits and vent 13 as well as hanger 17.

It is to be noted that the operation of our oxygenator is significantlysuperior to prior devices in employing an oxygenating device wherein thewals defining a blood flow passage are in face-to-face relation,producing a film-type flow of blood. promotes the stripping of a maximumamount of gas from the blood, which gas, if permitted to remain, mightcause an embolism. To

urther achieve the that type of blood passage found desirable, we spotheat seal together sheets 19 and 253 at a number of points in the bloodpassage, as at a in the defoaming chamber 25 and at 25b in the zigzagoutlet passage.

By providing a hat type of outlet passage promoting rm-like how ofblood, it is possible to discern at a glance whether all the entrapped"as has scavenged from the outlet passage. This could be irnp-ortant inemergency situations where the how of blood must be rapidly increased.With a thicker passageway, the opacity of the blood might mask anyentrapped gas.

The foregoing detailed descripn'on has been given for clearness ofunderstanding only and no unnecessary limitations are to be inferredtherefrom.

We claim:

1. A unitary, disposable blood oxygenator comprisprising a flexibleenvelope constructed of a pair of plastic sheets in face-to-facerelationship, with the side and upper edges thereof united by a heatseal, further heat seal lines connecting the sheets within the peripheryof the envelope defining a passageway through the envelope, a pair ofinlets at one end of the passageway, one inlet being connected to anoxygen source and the other inlet adapted to be connected to a supply ofvenous blood, at least one aperture through the upper portion of theenvelope for connecting the passageway with the atmosphere, and anoutlet at the other end of the passageway for discharging the oxygenatedblood.

2. In an oxygenation system for the oxygenation of blood comprising asource of oxygen, a source of blood, and an oxygenation device, theimproved oxygenation device which comprises a unitary disposable plasticblood oxygenator comprising a flexible envelope constructed or" a pairof plastic sheets in face-to-face relationship with the side and upperedges thereof united by a seal, further seals connecting the sheetswithin the periphery of the envelope thus defining a passageway throughthe envelope, a pair of inlets at one end of the passag way,

one inlet being adapted for connection to an oxygen source and the otherinlet adapted to be connected to a supply or" blood, at least oneaperture through the upper portion of the envelope for connecting thepassageway with the atmosphere and an outlet at the other end of thepassageway for discharging the oxygenated lood.

3. In an oxygenation system comprised of a source of blood, a source ofoxy en and an oxygenator, the improved oxygenator which comprises aunitary, disposale blood oxygenator, comprising a pair of substantiallyrectangular sheets of thermoplastic material disposed in face-to-face,lay-fiat relation and joined together along the two longer sides and anend to form an open-ended envelope, said envelope sheets beingadditionally joined together along a line parallel to and intermediatesaid sides to form a narrow, elongated oxygenating chamber, theintermediate joint extending from the open end of said e velope to apoint spaced from the closed end of said envelope, the end of saidoxygenating chamber adjacent the open end of said envelope being closedexcept for passages for introduction of venous blood and oxygen intosaid chamber, said envelope sheets being additionally joined togetheralong a transverse line to provide with the envelope end joint ade-foaming chamber adjacent the end of said oxygenating chamber adjacentthe closed end of said envelope, and said sheets being additionallyjoined together along spaced pairs of transverse lines to provide azigzag passage communicating with said de-foaming chamber and extendingto the open end of said envelope, and gas vent means in one of thejoints defining said de-foaming chamber.

4. The oxygenator of claim 3 in which said zigzag passage is equippedwith weir means at the areas thereof Where blood flowing therein changesits direction of flow.

5. The oxygenator of claim 3 in which said zigzag passage is enlarged atthe areas thereof where blood flowing therein changes its direction offlow.

6. In an oxygenation system comprised of a source of blood, a source ofoxygen and an oxygenator, the improved oxygenator which comprises a pairof generally rectangular thermoplastic sheets arranged in faceto-face,vertical relation, said sheets being united together along the upper endand two vertical sides thereof, hanger means associated with said upperend to support said device, said sheets being united together along avertically-extending line adjacent one of said vertical sides, saidvertically-extending line terminating a spaced distance from said upperend, the space between said vertically-extending line and said adjacentone vertical side providing an oxygenating chamber with the lower endthereof being closed except for entrance means for blood and oxygen,said sheets being additionally united along a second line extendinggenerally transversely and downwardly from the upper end of saidvertically-extending line and terminating adjacent to but spaced fromthe vertical side remote from said vertically-extending line to providea de-foaming chamber, said de-foaming chamber being provided with gasventing means to vent excess gases to the atmosphere, said sheets beingstill further united along a pair of generally parallel, inclined lines,one of which is connected with the end of said second line adjacent saidremote vertical side and the other of 10 which is connected to saidremote vertical side to provide an outlet.

7. The structure of claim 6, in which an upwardly- 6 extendingtongue-like projection is united to said sheets at the connection ofsaid one of said pair of inclined lines with said second line.

References Cited in the file of this patent UNITED STATES PATENTS2,784,716 Broman Mar. 12, 1957 2,848,995 Ryan Aug. 26, 1958 2,854,002 DeWall et a1 Sept. 30, 1958 OTHER REFERENCES Silicones and BloodCoagulation, by Jaques et al.; Canadian M.A.I., July 1946, vol. 55,pages 26-31.

1. A UNITARY, DISPOSABLE BLOOD OXYGENATOR COMPRISING A FLEXIBLE ENVELOPECONSTRUCTED OF A PAIR OF PLASTIC SHEETS IN FACE-TO-FACE RELATIONSHIP,WITH THE SIDE AND UPPER EDGES THEREOF UNITED BY A HEAT SEAL, FURTHERHEAT SEAL LINES CONNECTING THE SHEETS WITHIN THE PERIPHERY OF THEENVELOPE DEFINING A PASSAGEWAY THROUGH THE ENVELOPE, A PAIR OF INLETS ATONE END OF THE PASSAGEWAY, ONE INLET BEING CONNECTED TO AN OXYGEN SOURCEAND THE OTHER INLET ADAPTED TO BE CONNECTED TO A SUPPLY OF VENOUS BLOOD,AT LEAST ONE APERTURE THROUGH THE UPPER PORTION OF THE ENVELOPE FORCONNECTING THE PASSAGEWAY WITH THE ATMOSPHERE, AND AN OUTLET AT THEOTHER END OF THE PASSAGEWAY FOR DISCHARGING THE OXYGENATED BLOOD.